Reverse Blocking Voltage Research Articles

Design Considerations, Development, and Experimental Validation of a 3.3 kV SiC-Based Reverse Voltage Blocking Half Bridge Module for Current Source Inverter Application

Design Considerations, Development, and Experimental Validation of a 3.3 kV SiC-Based Reverse Voltage Blocking Half Bridge Module for Current Source Inverter Application

Reverse Blocking Enhancement‐Mode AlGaN/GaN HEMTs with Hybrid p‐GaN Ohmic Drain on the Si Substrates

Hybrid p‐GaN Ohmic drain reverse blocking high electron mobility transistors (RB‐HEMTs) and conventional p‐GaN Enhancement‐mode (E‐mode) HEMTs are designed and fabricated on the Si substrates. Compared with the conventional p‐GaN HEMT, the RB‐HEMT can achieve great reverse blocking capability. The forward and reverse blocking voltages of the RB‐HEMT are 1116 V and 1056 V and the turn‐on voltage of the device is 1.07 V. When the temperature rises from 25 °C to 150 °C, the turn‐on voltage of the RB‐HEMT increases from 1.07V to 1.10 V, and the Vth increases from 1.97V to 2.07 V. The difference in turn‐on voltage and threshold voltage is mainly due to the different metals in contact between the gate and drain electrodes and p‐GaN. The reverse leakage current of the RB‐HEMT is 1.16 × 10−1 mA mm−1 when the temperature is 150 °C, which still keep good reverse blocking ability at high temperatures.

A failure mechanism of IGBT module in MMC and improvement

In modular multi-level converter valves, as the blocked mode happens, the failure in IGBT modules often causes a chain explosion reaction, which masks the initial failure mechanism. The root cause of the failure was that the voltage, consisting of the diode forward voltage and the induced voltage on the parasitic inductance, exceeded the reverse blocking capability of the anti-parallel IGBT. The methods against the failure were studied from three aspects: decreasing the diode’s peak forward voltage, increasing the reverse blocking capability of IGBT, and minimizing the parasitic inductance of the package. It was found that the doping concentration’s effect on the diode’s peak forward voltage is not monotonic. It can be explained from the carrier density distribution during forward recovery transient that lower doping concentration reduces the carrier injection, and higher doping concentration reduces the excess carrier concentration in the doping region. Then, the influence of two buffer designs on the reverse blocking capability of IGBT was compared. It was found that a higher reverse blocking voltage would be achieved when a multi-proton implantation buffer replaced the diffused buffer. And the new design has almost no degradation in forward blocking capability.

Common Architectures and Devices for Current Source Inverter in Motor-Drive Applications: A Comprehensive Review

When compared to the much more common voltage-source inverter (VSI), the current-source inverter (CSI) is rarely used for variable speed drive applications, due to its disadvantages: the need of a constant DC-link current, typically realized with a front-end converter, and the need for reverse-voltage blocking (RVB) devices, typically implemented with in-series diodes. This limits the overall efficiency of the architecture. This paper investigates latest progress of the CSI research, with the aim of demonstrating why CSI could come back in the near future. Different architectures based on modern wide-bandgap (WBG) switches are analyzed, with an emphasis on why CSI can be advantageous compared to VSI.

FEM-based analysis of avalanche ruggedness of high voltage SiC Merged-PiN-Schottky and Junction-Barrier-Schottky diodes

Through comprehensive experimental measurements and TCAD simulation, it is shown that the avalanche ruggedness of SiC MPS & JBS diodes outperforms that of closely rated Silicon PiN diodes taking advantage of the wide-bandgap properties of SiC which leads to a high ionization and activation energy given the strong covalent bonds. Although the MPS diode structure favours a high reverse blocking voltage with small leakage current and a high current conduction, the localise current crowding caused by the multiple P+ implanted region leads to the avalanche breakdown at lower load currents than the SiC JBS diode. The results of Silvaco TCAD Finite Element modellings have a good agreement with the experimental measurements, indicating that SiC JBS diode can withstand the high junction temperature induced by avalanche in line with the calculated avalanche energy.

A High Reverse Breakdown Voltage p-GaN Gate HEMT with Field Control Drain

In this work, a high reverse blocking voltage (BV R) p-GaN gate high electron mobility transistor with field control drain (FCD-HEMT) has been proposed and fabricated. The FCD-HEMT features the field control drain (FCD), consisting of electrically shorted Ohmic contact structure and p-GaN cap. In the OFF-state, the 2-Dimensional Electron Gas (2DEG) channel is cut off due to the p-GaN cap introduced field control, which provides FCD-HEMT with reverse blocking capability. In the ON-state, the re-formed 2DEG channel offers a non-potential barrier pathway for electrons transfer from source to drain and ensures a low resistance of the FCD-HEMT. The fabricated device exhibits 1400 V forward breakdown voltage (BV F) and −1240 V reverse breakdown voltage (BV R), 12.7 mΩ·cm2 low specific ON-resistance, and 188 mA mm−1 max drain current while maintaining normally-OFF capability. These results demonstrate the great potential of FCD-HEMTs in 1200 V-class power applications.

Nb2O5 high-k dielectric enabled electric field engineering of β-Ga2O3 metal–insulator–semiconductor (MIS) diode

We demonstrate an Nb2O5/β-Ga2O3 metal–insulator–semiconductor (MIS) hetero-junction diode with Nb2O5 as the high-k dielectric insulator for more efficient electric field management resulting in enhanced breakdown characteristics compared to a β-Ga2O3 Schottky barrier diode. Nb2O5 dielectric films were grown using atomic layer deposition and exhibited a high dielectric constant of 50. The high dielectric constant resulted in a 5× lower electric field at the metal/dielectric interface in the MIS diode compared to the metal/β-Ga2O3 interface in the Schottky barrier diode. With good electron conduction in forward bias enabled by the negative conduction band offset of Nb2O5 with respect to β-Ga2O3, the MIS design led to a 3× improvement in the reverse blocking voltage with a slight trade-off in the specific on-resistance. Overall, a 3.3× increase in the power figure of merit was observed (3.25 MW/cm2 for the Schottky diode and 10.8 MW/cm2 for the MIS diode). A detailed analysis of the energy band line-up and the forward and reverse current transport mechanisms are also presented using analytical modeling and 2D technology computer-aided design simulations.

Optimization of Schottky-contact process on 4H-SiC Junction Barrier Schottky (JBS) Diodes

SiC Junction Barrier Schottky (JBS) Rectifier is a kind of unipolar power diode with low threshold voltage and high reverse blocking voltage. And the Schottky barrier Φ BN is a main technology parameter, which could greatly affect the forward conduction power and reverse leakage current in the JBS rectifiers. Therefore, it is necessary to balance the influence of Φ BN on the electrical characteristics of JBS rectifiers. In this paper, physical properties at the metal-semiconductor at the Schottky-contact could be optimized by the improvement of Schottky-contact process. And this optimization could significantly decrease Φ BN to reduce the on-state voltage drop V F and minimize negative impact on its reverse characteristics. After the completion of Silicon carbide JBS diodes, the static parameter electrical test was carried out on the wafer by using Keysight B1505A Power Device Analyzer/Curve Tracer. The test results show that the Schottky barrier height Φ BN of JBS Schottky rectifier manufactured by the modified Schottky foundation technology decreased from 1.19eV to 0.99eV and I R increased from 1.08μA to 3.73μA (reverse blocking voltage V R=1200V). It indicated that the power consumption of Schottky barrier junction in JBS rectifiers could be significantly reduced by about 25%, and I R could effectively be limited to less than 10μA.

Current-Source Inverter Integrated Motor Drives Using Dual-Gate Four-Quadrant Wide-Bandgap Power Switches

Four-quadrant (FQ) switches that have both bidirectional current and reverse-voltage blocking (RVB) capabilities are appealing candidates for use in current-source inverters (CSI) to significantly reduce the switch conduction losses. However, the FQ characteristics of these switches can create problems during switching events by causing transient overcurrent pulses that damage the inverter. Commutation methods for FQ switches in CSI topologies that address these challenges are presented in this article. Several key aspects of the performance and implementation of these commutation methods are explored for a high-power density 3 kW integrated motor drive incorporating both a current-source active rectifier and inverter stage that has been developed using these FQ switch methods. Experimental results demonstrate the benefits of implementing these commutation methods in CSIs that use FQ switches. The benefits include substantial efficiency improvement compared to the conventional CSI implemented with series power diodes as well as reduced mass and volume of passive components due to the high switching frequency (100 kHz).

Design of PAMBE-based selective-area growth compliant ultra-low leakage GaN mixed-conduction vertical diodes for high-power applications * *This work was supported by the Office of Naval Research (ONR) under the ONR Award N00014-17-1-2681 (Program Manager: Lynn J Petersen).

Modern high-speed power applications require diodes with high-current capacity, larger reverse blocking voltage, lower reverse recovery transients, and lower leakage. GaN mixed-conduction vertical diodes are an attractive option for these operations. Experimentally reported GaN diodes have two major shortcomings, namely, higher leakage due to non-optimum design and conventional processing methods (e.g. ion implantation and dry etching), introducing huge leakage components. In this work, we design ultra-low leakage GaN buried p-base merged p–i–n Schottky and buried p-base merged p–i–n junction barrier controlled Schottky diodes, capable of reducing leakage current by more than five orders of magnitude by virtue of strong reduced surface field effect. Moreover, these designs are fully compliant with our earlier reported silicon nitride shadowed selective-area growth (SNS-SAG) methodology, capable of reducing the leakage by at least four orders of magnitude. In combination with SNS-SAG and highly efficient dielectric vertical sidewall edge termination scheme, these designs provide attractive options for higher performance.

1.3 kV Reverse-Blocking AlGaN/GaN MISHEMT With Ultralow Turn-On Voltage 0.25 V

A reverse-blocking AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor (RB-MISHEMT) is proposed and fabricated. Compared with the conventional MISHEMT with ohmic drain, the proposed device features a hybrid Schottky-ohmic drain with a low work function Tungsten (W), based on which the state-of-the-art ultralow turn-on voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V} _{\mathrm{ on}}$ </tex-math></inline-formula> ) of 0.25 V could be realized without degradation in on-state characteristics. In addition, the fabricated RB-MISHEMT exhibits the excellent reverse blocking voltage of −1332 V (at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V} _{\mathrm{ GS}}= 0$ </tex-math></inline-formula> V) and forward blocking voltage of 1315 V (at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V} _{\mathrm{ GS}} = -15$ </tex-math></inline-formula> V) with a specific on-resistance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R} _{\mathrm{ on,sp}}$ </tex-math></inline-formula> ) of 3.5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}\Omega $ </tex-math></inline-formula> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , leading in the highest power figure-of-merit (FOM) of > 494 MW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The good thermal stability could also be observed in fabricated RB-MISHEMT. The corresponding operation mechanism of RB-MISHEMT are also revealed by Silvaco ATLAS simulations. These results demonstrate the great potential in power electronics applications.

Design and Fabrication of Vertical Metal/TiO2/β-Ga2O3Dielectric Heterojunction Diode With Reverse Blocking Voltage of 1010 V

This work provides insight into the design principles and the reasonable construction of Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> heterojunction diode. We chose TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> grown by atomic layer deposition (ALD) as a suitable insulator with a small conduction band offset of TiO<;span style="font-size: 14.5px;"> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /<;/span> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">β</i> -Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> heterojunction and a large dielectric constant. The type-I band alignment of the TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> / <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">β</i> -Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> heterojunction was obtained using X-ray photoelectron spectroscopy (XPS). We demonstrated a high-performance vertical metal/TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> / <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">β</i> -Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> dielectric heterojunction diode with reverse blocking voltage of 1010 V and differential ON-resistance of 3.3 mΩ·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The proposed design principles of dielectric heterojunction diode and the insulator selection can also provide a simple, effective, and feasible technology for other wideband and ultrawideband semiconductors in which bipolar doping is challenging to achieve high power device performance.

Characterization of the radiation tolerance of cryogenic diodes for the High Luminosity LHC inner triplet circuit

Cryogenic bypass diodes are part of the baseline powering layout for the circuits of the new ${\mathrm{Nb}}_{3}\mathrm{Sn}$ based final focus magnets of the high luminosity Large Hadron Collider. They will protect the magnets against excessive transient voltages during a nonuniform quenching process. The diodes are located inside an extension to the magnet cryostat, operated in superfluid helium and exposed to ionizing radiation. Therefore, the radiation tolerance of different types of diodes has been tested at cryogenic temperatures in CERN's CHARM irradiation test facility during its 2018 run. The forward bias characteristics, the turn-on voltage and the reverse blocking voltage of each diode were measured weekly at 4.2 K and 77 K, as a function of the accumulated radiation dose. The diodes were submitted to a total dose close to 12 kGy and a 1 MeV neutron equivalent fluence of $2.2\ifmmode\times\else\texttimes\fi{}{10}^{14}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}2}$. After the end of the irradiation program the annealing behavior of the diodes was tested by increasing the temperature slowly to 293 K. This paper describes the experimental setup, the measurement procedure and the analysis of the measurements performed during the irradiation program as well as the results of the annealing study.

Demonstration of a 2 kV Al0.85Ga0.15N Schottky Barrier Diode With Improved On-Current and Ideality Factor

In this letter, we report on demonstrating a Schottky barrier diode (SBD) with high reverse blocking voltage by incorporating an ultra-wide bandgap semiconductor Al0.85 Ga0.15 N channel. Benefited from the lower activation energy of the Si in GaN, the net carrier concentration of Al0.85 Ga0.15N can be essentially enhanced to ${2}\times {10}^{{17}}$ cm−3 level with surface roughness of 0.33 nm. Due to the good material property, a reverse blocking voltage of 2 kV and room temperature ideality factor of 2.3 are demonstrated. Combined with the significantly improved on-current and on/off ratio of more than 106 when compared with other AlN SBDs, Al0.85 Ga0.15 N turns out to be a competitive AlN counterpart by considering the compromise among ultra-wide bandgap, dopant activation, and material property.

Interfacial Impurities and Their Electronic Signatures in High‐Voltage Regrown Nonpolar m‐Plane GaN Vertical p–n Diodes

Impacts of silicon, carbon, and oxygen interfacial impurities on the performance of high‐voltage vertical GaN‐based p–n diodes are investigated. The results indicate that moderate levels (≈5 × 1017 cm−3) of all interfacial impurities lead to reverse blocking voltages (Vb) greater than 200 V at 1 μA cm−2 and forward leakage of less than 1 nA cm−2 at 1.7 V. At higher interfacial impurity levels, the performance of the diodes becomes compromised. Herein, it is concluded that each impurity has a different effect on the device performance. For example, a high carbon spike at the junction correlates with high off‐state leakage current in forward bias (≈100× higher forward leakage current compared with a reference diode), whereas the reverse bias behavior is not severely affected (&gt; 200 V at 1 μA cm−2). High silicon and oxygen spikes at the junction strongly affect the reverse leakage currents (≈ 1–10 V at 1 μA cm−2). Regrown diodes with impurity (silicon, oxygen, and carbon) levels below 5 × 1017 cm−3 show comparable forward and reverse results with the reference continuously grown diodes. The effect of the regrowth interface position relative to the metallurgical junction on the diode performance is also discussed.

Theoretical and Experimental Study of 13.4 kV/55 A SiC PiN Diodes with an Improved Trade-Off between Blocking Voltage and Differential On-Resistance.

In this paper, a 13.4 kV/55 A 4H-silicon carbide (SiC) PiN diode with a better trade-off between blocking voltage, differential on-resistance, and technological process complexity has been successfully developed. A multiple zone gradient modulation field limiting ring (MGM-FLR) for extremely high-power handling applications was applied and investigated. The reverse blocking voltage of 13.4 kV, close to 95% of the theoretical value of parallel plane breakdown voltage, was obtained at a leakage current of 10 μA for a 100 μm thick, lightly doped, 5 × 1014 cm−3 n-type SiC epitaxial layer. Meanwhile, a fairly low differential on-resistance of 2.5 mΩ·cm2 at 55 A forward current (4.1 mΩ·cm2 at a current density of 100 A/cm2) was calculated for the fabricated SiC PiN with 0.1 cm2 active area. The highest Baliga’s figure-of-merit (BFOM) of 72 GW/cm2 was obtained for the fabricated SiC PiN diode. Additionally, the dependence of the breakdown voltage on transition region width, number of rings in each zone, as well as the junction-to-ring spacing of SiC PiN diodes is also discussed. Our findings indicate that this proposed device structure is one potential candidate for an ultra-high voltage power system, and it represents an option to maximize power density and reduce system complexity.

Developing the Guard Ring Topology of Power Silicon Diodes with a Blocking Voltage of up to 6.7 kV

High-voltage fast recovery diodes (FRDs) are characterized by a small forward voltage drop and low power dissipation. The main characteristics of such diodes is the reverse blocking voltage or the breakdown voltage. The aim of this work is to develop a guard ring topology allowing us to obtain the maximum possible blocking voltage of the diode and definite localization of the breakdown place under the conditions of the standard technological processes and without using new materials or substrates. The topology of the high-voltage part of silicon fast recovery power diodes is developed to obtain the maximum reverse blocking voltage. The calculations are carried out in the TCAD environment in the structure editor of which we included a program for the automatic creation of device models with dimensions of about several millimeters. The arrangement of guard rings is calculated according to the proposed principle allowing us to obtain power diodes with different breakdown voltages. The topology is developed so that the breakdown occurs under the edge of the active region, which guarantees the absence of catastrophic failures of the device. Power fast recovery diodes manufactured according to the proposed topology have the maximum reverse blocking voltage within the range of 3.3–6.7 kV, which indicates the reliability of the calculation methodology.

The Rebirth of the Current Source Inverter: Advantages for Aerospace Motor Design

It is well known and widely accepted that the voltage source inverter (VSI) now dominates the world of electrical drives. Its success is probably due to its simplicity, high efficiency, and the widespread availability of VSs. This popularity has, in turn, influenced the evolution of the semiconductor industry, which has focused in recent years on devices tailored for VSIs. Thus, products such as depletion devices (normally off) and those without reverse voltage blocking have been widely marketed and used.

More Than 3000 V Reverse Blocking Schottky-Drain AlGaN-Channel HEMTs With &gt;230 MW/cm2 Power Figure-of-Merit

In this letter, more than 3000 V reverse blocking Schottky-drain AlGaN-channel HEMTs are demonstrated for the first time. By using Schottky drain technology, forward breakdown voltage $\text{V}_{\textsf {FB}}$ (at 10 $\mu \text{A}$ /mm) is improved from 1850~2100 V to 2200~2600 V for ${L} _{\textsf {GD}}=\textsf {22}\mu \text{m}$ . Due to the high breakdown electric field of AlGaN material, reverse blocking voltage ${V} _{\textsf {RB}}$ (at 10 $\mu \text{A}$ /mm) reaches as high as −1950 ~ −2200 V. For HEMTs with ${L} _{\textsf {GD}}=\textsf {52}\mu \text{m}$ , record high ${V} _{\textsf {FB}}$ of >3000 V and ${V} _{\textsf {RB}}$ of >3000 V have been achieved. The leakage current is as low as 6.06 nA/mm at ${V} _{\textsf {DS}}=-\textsf {2000}$ V.

High-Performance Vertical $\beta$ -Ga2O3Schottky Barrier Diode With Implanted Edge Termination

This work reports on implementing Mg implanted Edge Termination (ET), a simple but very useful technique to increase the breakdown voltage (BV) of the vertical $\beta $ -Ga2O3 Schottky barrier diode (SBD). With this ET, vertical $\beta $ -Ga2O3 SBD demonstrates a reverse blocking voltage of 1.55 kV and low specific on-resistance ( ${R} _{ \mathrm{\scriptscriptstyle ON},\textrm {sp}}$ ) of 5.1 $\text{m}\Omega \cdot \textrm {cm}^{\textrm {2}}$ at a lightly doped $\beta $ -Ga2O3 layer with epitaxial thickness of $10~\mu \text{m}$ , yielding a high power figure-of-merit (P-FOM) of 0.47 GW/cm2. Combined with high forward current on/off ratio of 108 ~ 109, Schottky barrier height of 1.01 eV, and ideality factor of 1.05, vertical $\beta $ -Ga2O3 Schottky Diode with implanted ET verifies its great potential for future power rectifiers.